DPP: Testing capability to generate invalid PKEX encrypted key (M and N)

Signed-off-by: Jouni Malinen <jouni@qca.qualcomm.com>

diff --git a/src/common/dpp.c b/src/common/dpp.c
index 97a618af1ca0a9b9706d6d78ca883ef01cbbe115..7f5046a2f1829903c1fc0fc2a6cfac7f3e3ecad4 100644 (file)
--- a/src/common/dpp.c
+++ b/src/common/dpp.c
@@ -5468,6 +5468,77 @@ fail:
 }
 
 
+#ifdef CONFIG_TESTING_OPTIONS
+static int dpp_test_gen_invalid_key(struct wpabuf *msg,
+                                   const struct dpp_curve_params *curve)
+{
+       BN_CTX *ctx;
+       BIGNUM *x, *y;
+       int num_bytes, offset;
+       int ret = -1;
+       EC_GROUP *group;
+       EC_POINT *point;
+
+       group = EC_GROUP_new_by_curve_name(OBJ_txt2nid(curve->name));
+       if (!group)
+               return NULL;
+
+       ctx = BN_CTX_new();
+       point = EC_POINT_new(group);
+       x = BN_new();
+       y = BN_new();
+       if (!ctx || !point || !x || !y)
+               goto fail;
+
+       if (BN_rand(x, curve->prime_len * 8, 0, 0) != 1)
+               goto fail;
+
+       /* Generate a random y coordinate that results in a point that is not
+        * on the curve. */
+       for (;;) {
+               if (BN_rand(y, curve->prime_len * 8, 0, 0) != 1)
+                       goto fail;
+
+               if (EC_POINT_set_affine_coordinates_GFp(group, point, x, y,
+                                                       ctx) != 1)
+                       goto fail;
+
+               if (!EC_POINT_is_on_curve(group, point, ctx))
+                       break;
+       }
+
+       num_bytes = BN_num_bytes(x);
+       if ((size_t) num_bytes > curve->prime_len)
+               goto fail;
+       if (curve->prime_len > (size_t) num_bytes)
+               offset = curve->prime_len - num_bytes;
+       else
+               offset = 0;
+       os_memset(wpabuf_put(msg, offset), 0, offset);
+       BN_bn2bin(x, wpabuf_put(msg, num_bytes));
+
+       num_bytes = BN_num_bytes(y);
+       if ((size_t) num_bytes > curve->prime_len)
+               goto fail;
+       if (curve->prime_len > (size_t) num_bytes)
+               offset = curve->prime_len - num_bytes;
+       else
+               offset = 0;
+       os_memset(wpabuf_put(msg, offset), 0, offset);
+       BN_bn2bin(y, wpabuf_put(msg, num_bytes));
+
+       ret = 0;
+fail:
+       BN_free(x);
+       BN_free(y);
+       EC_POINT_free(point);
+       BN_CTX_free(ctx);
+
+       return ret;
+}
+#endif /* CONFIG_TESTING_OPTIONS */
+
+
 static struct wpabuf * dpp_pkex_build_exchange_req(struct dpp_pkex *pkex)
 {
        EC_KEY *X_ec = NULL;
@@ -5556,6 +5627,15 @@ skip_finite_cyclic_group:
        wpabuf_put_le16(msg, DPP_ATTR_ENCRYPTED_KEY);
        wpabuf_put_le16(msg, 2 * curve->prime_len);
 
+#ifdef CONFIG_TESTING_OPTIONS
+       if (dpp_test == DPP_TEST_INVALID_ENCRYPTED_KEY_PKEX_EXCHANGE_REQ) {
+               wpa_printf(MSG_INFO, "DPP: TESTING - invalid Encrypted Key");
+               if (dpp_test_gen_invalid_key(msg, curve) < 0)
+                       goto fail;
+               goto out;
+       }
+#endif /* CONFIG_TESTING_OPTIONS */
+
        num_bytes = BN_num_bytes(Mx);
        if ((size_t) num_bytes > curve->prime_len)
                goto fail;
@@ -5686,6 +5766,15 @@ skip_status:
        wpabuf_put_le16(msg, DPP_ATTR_ENCRYPTED_KEY);
        wpabuf_put_le16(msg, 2 * curve->prime_len);
 
+#ifdef CONFIG_TESTING_OPTIONS
+       if (dpp_test == DPP_TEST_INVALID_ENCRYPTED_KEY_PKEX_EXCHANGE_RESP) {
+               wpa_printf(MSG_INFO, "DPP: TESTING - invalid Encrypted Key");
+               if (dpp_test_gen_invalid_key(msg, curve) < 0)
+                       goto fail;
+               goto skip_encrypted_key;
+       }
+#endif /* CONFIG_TESTING_OPTIONS */
+
        num_bytes = BN_num_bytes(Nx);
        if ((size_t) num_bytes > curve->prime_len)
                goto fail;

diff --git a/src/common/dpp.h b/src/common/dpp.h
index f50948b9e3f3e0d1e999d34711cd979d42a129e5..51a763cbdf14eb865b804951cfb6d78cb27d7999 100644 (file)
--- a/src/common/dpp.h
+++ b/src/common/dpp.h
@@ -256,6 +256,8 @@ enum dpp_test_behavior {
        DPP_TEST_NO_BOOTSTRAP_KEY_PKEX_CR_RESP = 41,
        DPP_TEST_NO_R_AUTH_TAG_PKEX_CR_RESP = 42,
        DPP_TEST_NO_WRAPPED_DATA_PKEX_CR_RESP = 43,
+       DPP_TEST_INVALID_ENCRYPTED_KEY_PKEX_EXCHANGE_REQ = 44,
+       DPP_TEST_INVALID_ENCRYPTED_KEY_PKEX_EXCHANGE_RESP = 45,
 };
 
 extern enum dpp_test_behavior dpp_test;